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| United States Patent |
5,238,597
|
|
Fritsche-Lang
, et al.
|
August 24, 1993
|
Sucrosetricarboxylic acid and compositions containing the same
Abstract
Sucrosetricarboxylic acid can be prepared by oxidizing sucrose with oxygen,
if desired in a mixture with inert gases, by means of a more effective
catalyst than platinum/alumina.
The product can be used in washing agents or as a food additive.
| Inventors:
|
Fritsche-Lang; Wolfram (Bensheim, DE);
Leupold; Ernst I. (Neu-Anspach, DE);
Schlingmann; Merten (Konigstein/Taunus, DE)
|
| Assignee:
|
Hoechst Aktiengesellschaft (Frankfurt am Main, DE)
|
| Appl. No.:
|
659479 |
| Filed:
|
February 25, 1991 |
Foreign Application Priority Data
| Current U.S. Class: |
426/658; 510/471; 536/4.1 |
| Intern'l Class: |
C07H 003/00; A23G 003/00; C11D 017/00 |
| Field of Search: |
536/1.1
426/658
252/174.18
514/53
|
References Cited
U.S. Patent Documents
| 2845439 | Jul., 1958 | Reiners | 536/124.
|
| 3894146 | Jul., 1975 | Tsuyama | 536/4.
|
| 3910880 | Oct., 1975 | Lamberti | 536/4.
|
| 4108891 | Aug., 1978 | Hattori et al. | 260/528.
|
Other References
Nieuwenhuizen et al, Polycarboxylic Acids Containing Acetal Functions:
Calcium Sequestering Compounds Based on Oxidized Carbohydrates, J. An.
Oil. Chem. Soc. 1983, vol. 60 pp. 120-124.
Hawley's Condensed Chemical Dictionary, p. 35.
Chemical Abstracts, vol. 98, Abstract No. 109302z.
T. A. Downey, Organic Chelating Agents, Soap and Chemical Specialties 42
(2) pp. 52-55, 105 and 106 (1966).
O. Theaner, Carbohydrate Chemistry, Pgman-Horton, vol. 1B (1980) pp. 1014
and 1015.
Ullmann's Encyklopadie der Technischen Chemie, vol. 24, p. 787 (1983).
|
Primary Examiner: Brown; Johnnie R.
Assistant Examiner: Peselel; Elli
Attorney, Agent or Firm: Finnegan, Henderson, Farabow, Garrett & Dunner
Parent Case Text
This application is a continuation of application Ser. No. 07/449,421,
filed Dec. 15, 1989 now abandoned, which was a continuation of Ser. No.
06/915,031, filed Oct. 3, 1986, now abandoned.
Claims
We claim:
1. The compound
.beta.-D-arabinofuranaric-2-hexulosyl-.alpha.-D-glucopyranosiduronic acid
or the sodium salt thereof.
2. A food composition containing, as an additive, an effective amount of a
compound as claimed in claim 1.
3. A washing formulation containing, as an additive, an effective amount of
a compound as claimed in claim 1.
Description
The present invention relates to sucrosetricarboxylic acid and its
secondary products such as salts, lactones, esters, amides and the like,
to a process for preparing and using the same.
It is known that the catalytic oxidation of carbohydrates, specifically
that of the primary hydroxymethyl groups contained therein, proceeds
slowly and in most cases non-uniformly. For instance, oligomeric
carbohydrates such as branched arabinoxylan from rye flour are oxidized in
4 days at 65.degree. C. in only 4% to uronic acids. It is true that the
oxidation of sucrose has also been mentioned, but statements about the
isolation of the reaction products were not mentioned at the time. It was
merely stated that it was found in a subsequent total hydrolysis that the
hydrolyzate contained only small amounts of glucuronic acid.
The oxidation of sucrose with a platinum-alumina catalyst and oxygen has
also been previously described (German Patent 886,305, Example 3 and the
corresponding U.S. Pat. No. 2,845,439, Example 4). After a 6-hour
treatment this oxidation gave only 60% of the theoretically expected yield
of the corresponding glucuronic acid derivative. However, the isolation of
this compound is not described.
The invention provides, then, sucrosetricarboxylic acid (i.e.
(.beta.-D-arabinofuranaric-2-hexulosyl)-.alpha.-D-glucopyrano-siduronic
acid) of the formula
##STR1##
The invention further provides a process for preparing sucrosetricarboxylic
acid, which comprises oxidizing sucrose with oxygen, if desired in a
mixture with inert gases, for example in the form of air, by means of a
significantly more effective catalyst than platinum/alumina. Suitable
catalysts are those of platinum metals, such as palladium, but in
particular platinum itself, on activated carbon, in particular the more
active types. These generally contain 5-10% by weight of metal, in
particular platinum. In addition to a distinct increase in the rate of
oxidation, an increased selectivity of the oxidation between primary and
secondary hydroxyl groups of the carbohydrates, in particular of
nonreducing carbohydrates, is achieved. Preferably the oxidation is
carried out by treating the solid catalyst in an aqueous reaction medium
with gaseous oxygen, i.e. in a three-phase reaction. This three-phase
reaction is carried out for example in a bubble column reactor which can
be operated not only batchwise but also continuously. In preferred
embodiments, highly concentrated oxygen is used and the reaction solution
is recycled, which facilitates setting, and keeping constant, the pH. It
is within the capacity of the skilled worker to set the reaction solution
to a selected and suitable reaction temperature and to optimize the
concentration ratio of substrate/catalyst or substrate/oxygen.
The process according to the invention is generally carried out at
30.degree. C. to the boil, preferably at 50.degree. to 95.degree., in
particular 60.degree. to 90.degree. C. In general, atmospheric pressure is
employed, but it is also possible to employ superatmospheric pressure,
which is a way of increasing the supply of oxygen and/or the reaction
temperature. In the process according to the invention, maintaining
certain sucrose concentrations is particularly advantageous;
concentrations below 5% by weight easily give rise to an over-oxidation
and above 20% by weight only to comparatively low conversions under
atmospheric pressure. In general, pH values of 5 to 9, preferably 6 to 8,
are used. The course of the reaction can be monitored by sampling, for
example by means of gas chromatography analysis of the derivatized, for
example silylated, products.
The sucrosetricarboxylic acid formed is generally obtained in a mixture
with less oxidized intermediates, i.e. various monocarboxylic and/or
dicarboxylic acids. The oxidation can be discontinued at as early a stage
as a tricarboxylic content of at least 20%. However, the oxidation is
generally continued until at least 30 or 40 and preferably more than 60 or
70% of sucrosetricarboxylic acid has been formed. This
sucrosetricarboxylic acid can be concentrated and isolated out of the
reaction mixture in a conventional manner.
The process according to the invention can be carried out, for example, in
a jacketed reactor which holds the suspension of the catalyst in the
aqueous medium and which contains at the bottom a frit or another
correspondingly suitable porous membrane and through which a gas stream,
very finely divided by this separating membrane, flows from the underside.
For economic and safety reasons, the oxygen is expediently passed through
the reaction medium at such a rate that the catalytically activated oxygen
is just consumed at the upper end of the bubble column. To improve the
degree of mixing and to prolong the time of exposure to the oxygen, it can
be advantageous to stir the reaction mixture.
On account of its chemical structure or structural elements, the
sucrosetricarboxylic acid formed is suitable as such or in the form of its
immediately obtainable reaction products, i.e. in particular mixtures with
the intermediates, for applications in the field of complexing agents, for
example analogously to gluconic acid and glucaric acid in washing agent
formulations, as food additives, for example for the applications
customary for citric acid, as a polyfunctional reactant (crosslinking) and
also as a starting material for chemical reactions (hydrophilizing
reagent).
The process according to the invention has made it possible to carry out
the oxidation of sucrose in such a way as to form the hitherto unknown
sucrosetricarboxylic acid.
EXAMPLES
1) In an externally heated, upright glass tube (diameter: 50 mm, length: 80
cm) having a frit bottom and, installed at a point slightly thereabove, a
discharge means for the reaction mixture, a stream of oxygen (about 25
liters (S.T.P.)/h) flows upwardly through a solution of 120 g of sucrose
in 1.2 liters of water and also 60 g of added platinum catalyst (5% of
Pt/active carbon). The acids formed by the oxidation are wholly or partly
converted into the sodium salts either by feeding in sodium hydroxide
solution, with the attendant possibility of pH control, or by means of the
corresponding molar amounts of initially introduced sodium
hydrogencarbonate. At a temperature of 80.degree. C. in the oxidation and
neutralization and a pH of 6.5 held constant during both stages, the
products have after silylation and according to gas chromatography
analysis the following compositions as a function of the reaction time
(see Table 1):
TABLE 1
______________________________________
Composition of oxidation products as a function
of reaction time (in percent)
6 h 12 h 18 h
______________________________________
Sucrose consumed -- --
Monocarboxylic acids
20.9 5.2 1.5
(2 isomers)
Dicarboxylic acids
38.9 39.6 29.7
(2 isomers)
Tricarboxylic acid I
5.1 22.3 35.3
______________________________________
The reaction solution is filtered to remove the catalyst, and the filtrate
is concentrated in a thin film evaporator and freeze-dried. Yield 104 g
(86.7% by weight). The total acid content is 7.18 mEq/g (theoretical value
for sucrosetricarboxylic acid 7.80 mEq/g).
To characterize the sucrosetricarboxylic acid (STA), the reaction mixture
is converted by means of commercially available cation exchanger into the
free acids and freeze-dried after filtration. After complete acetylation
with an excess of acetic anhydride and equimolar amounts of
p-toluenesulfonic acid (20.degree. C., 20 h), the sirupy residue is
chromatographed over silica gel (eluent: methylene chloride/methanol 10:1
v.v.). The pentaacetylated sucrosetricarboxylic acid obtained last with
polar eluent in the chromatography is converted with catalytic amounts of
sodium methanolate in methanol into the trisodium salt.
.sup.1 H-NMR (D.sub.2 O, 400 MHz): .delta.=5.45 (d,H-1',J.sub.1',2' =3.75
Hz), 4.23-4.12 (m, H-5',H-3,H-4,H-5), 3.82, (struct. t, H-3'), J.sub.3',4'
=9.5 Hz, J.sub.2',3' =9.8 Hz), 3.54 (dd, H-2', J.sub.1',2' =3.75 Hz,
J.sub.2',3' =9.8 Hz), 3.45 (struct. t,H-4',J.sub.3',4' =J.sub.4',5' =9.5
Hz).
GC-MS (gas chromatography/mass spectroscopy) (after silylation, chemical
ionization with isobutane) m/z=961 (M+1-fragment of the 8-fold silylated
compound, relative intensity about 0.1%).
FAB-MS (fast atom bombardment) (sodium salt used, glycerol as matrix)
m/z=451 (MH.sup.+, relative intensity 36%).
2) By the method of Example 1, 120 g of sucrose, dissolved in 1.2 liters of
water, are oxidized at 60.degree. C. and pH 7.5 in a stream of oxygen.
Table 2 shows the compositions determined by GC analysis.
TABLE 2
______________________________________
Composition of oxidation products as a function
of reaction time (in percent)
8 h 28 h 52 h 84 h
______________________________________
Sucrose 1.1 -- -- --
Monocarboxylic acids
28.9 10.3 5.7 4.7
(2 isomers)
Dicarboxylic acids
35.8 36.1 27.3 23.0
(2 isomers)
Oxalic acid 5.9 10.8 12.6 10.9
Tricarboxylic acid I
4.6 20.7 32.7 40.9
______________________________________
Filtration to remove the catalyst and freeze-drying the filtrate leaves
93.8 g (78.0% by weight).
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